Went down river, having gone outside (9)
I believe the answer is:
decreased
'gone outside' is the definition.
The answer and definition can be both related to change as well as being past participle verbs.
Maybe there's an association between them I don't understand?
'went down river' is the wordplay.
I cannot really see how this works, but
'went' could be 'eased' (easing is a kind of going) and 'eased' is present in the answer.
'down' could be 'd' and 'd' is located in the answer.
'river' could be 'r' (abbreviation for river) and 'r' is found in the answer.
This explanation may well be incorrect...
'having' acts as a link.
Can you help me to learn more?
(Other definitions for decreased that I've seen before include "Dropped" , "contracted" , "Became smaller or fewer" .)